How to check if a string is numeric? [duplicate]

Answer 1

Simple method:

public boolean isBlank(String value) {
    return (value == null || value.equals("") || value.equals("null") || value.trim().equals(""));
}


public boolean isOnlyNumber(String value) {
    boolean ret = false;
    if (!isBlank(value)) {
        ret = value.matches("^[0-9]+$");
    }
    return ret;
}